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Given two swallowing series:

  • 1st – Standing dorsal view
  • 2nd – Standing lateral view
  • Oral phase (ie. Bolus formation) is normal and most swallowing events resulted in smooth transition from cricopharyngeal phase to esophageal phase
  • Cricopharyngeal phase is abnormal with the occurrence of multiple aspirations; Aspiration associated with episodic incomplete stripping of pharyngeal barium rather than incomplete epiglottis occlusion of tracheal opening (both accepted)
  • Aspiration occurred to the level of the caudal principle bronchi, but never into the alveolar level, with coughing events clearing majority into the nasal and common pharynx (few candidates recognized coughing)
  • Moderate esophageal dysmotility particularly in caudal thoracic esophagus; normal primary peristaltic wave initiation then mild delays in cranial thoracic esophagus were cleared by secondary peristalsis
  • Retrograde bolus movement associated with caudal esophagus that was preceded by moderate esophageal distention as secondary peristaltic wave propagated to hiatus. Reflux was also accepted as small amounts were refluxed but this was less than the former
  • Normal gastric position with some greater curvature flattened that likely represented the prior gastropexy site
  • No evidence of pyloric outflow or hypertrophy
  • M – Dysphagia – multilevel at cricopharyngeal and gastroesophageal phases
  • M – Aspiration of barium into the respiratory tree (expected to be cleared by mucociliary apparatus – see nuclear scinitigraphy studies as reference).
  • m – no evidence of gastropexy failure

 

 

KEY:

M: major findings

m: minor findings

  • Cricopharyngeal – no structural abnormality identified, therefore, cranial nerve and/or neuromuscular disorder considered.
  • Caudal esophageal – Altered anatomy secondary to gastropexy.

Neurologic consult and +/-MRI because the cricopharyngeal dysphagia considered more clinically significant.

Thoracic radiographs was given by all candidates – no point were awarded, as while it was an appropriate course of action it was not pivotal to answering the clinical question

This case was generally very poorly done, even though examiners felt it was generously graded. For example, the final diagnosis given by candidates was rarely any form of dysphagia.  The performance on this case speaks to poor foundational knowledge on swallowing and esophageal pathyphysiology and the interpretation of these examinations.  Many candidates struggled with time management in this section and were behind the 7 minutes per case pace at the point this case was encountered, and often in spite of being warned about time and that this case in particular had cine loops to review.  There were successful candidates within this time-strapped group, so it is difficult to definitively determine the effect of time pressure.

The successful candidates systematically worked through the different phases of the swallowing study and correctly determined the cricopharyngeal phase was most significant, as aspiration should not occur.  In all instances, these candidates manipulated the cine loop to observe the cricopharyngeal phase frame-by-frame in accordance with literature recommendations.  As a result, these candidates frequently determined the next correct step in the clinical course being a neurologic consultation or examination. A laryngeal examination was also accepted for those candidates concerned for laryngeal paralysis as a potential cause of aspiration.

100% of candidates recognized and/or reacted immediately (and almost viscerally!) to the aspiration of barium in the trachea.  Unfortunately, this is also where a lot of unsuccessful candidates stopped considering the significance of this finding. Other unsuccessful candidates noted the dog would be fine with this amount of aspiration, which is technically true but significantly minimizes the importance of REPEATED episodes of aspiration. Some unsuccessful candidates seemed to have been biased by the history or regurgitation, vomiting and prior gastropexy and tended to focus more time reviewing the caudal esophageal motility.  Most candidates, successful and unsuccessful, thought there was more regurgitation rather than retrograde bolus movement from the caudal esophageal sphincter; the opposite is true.  Both, however, were accepted. Some unsuccessful candidates convinced themselves there was a paraesophageal hernia or a problem at the pylorus. Some candidates diagnosed aspiration pneumonia of barium, which is not present in these images.  Esophagitis and/or GERD were the most frequently given differential diagnoses for the unsuccessful candidates.  Unsuccessful candidates often received no points for recommendations because of their focus on the caudal esophagus, with recommendations medical management (ie. feed upright or meatballs, administer medications (ie. sucrafate or prokinetics) or get a surgery consult for revision of gastropexy).  Finally, although the clinical question was specifically stated in the information slide, unsuccessful candidates failed to answer the clinical question.

The provided study is actually the second swallowing this dog had following gastropexy where aspiration was also identified. At the conclusion of the second swallowing study, a neurologic exam was recommended by radiology and atrophy of half of the tongue was identified. In the subsequent MRI examination, a right-sided tumor involving the emerging cranial nerves of the mid and caudal medulla oblongata was detected.